The manufacture, sale and operation of automobile laundering equipment is big business in the United States and many other countries. The term “automobile laundering”, as used herein, refers to wet washing the external surfaces of virtually any type of vehicle from ordinary passenger cars to busses, trucks, vans and even train cars and airplanes. Moreover, the principles and structures described herein can be applied to any fluid spray system including, by way of example, painting, prepping and corrosion-proofing.
One of the most popular forms of vehicle laundering equipment is the so-called “rollover” washer which is characterized by a washing structure which moves over or around a vehicle parked in a pre-specified area. Rollover equipment typically occupies less space than the traditional tunnel or conveyor washer and is often preferred by car dealers, service stations and convenience stores with collateral vehicle laundries for that reason.
Rollover washers can have brushes which contact the surfaces of the vehicle; see for example U.S. Pat. No. 3,428,983 issued Feb. 25, 1969 to R. Seakan and U.S. Pat. No. 4,453,284 issued Jun. 12, 1984 to R. Schleeter. An alternative approach, preferred by many because of the absence of physical contact between the washing apparatus and the vehicle, is the pressure washer, an example of which is illustrated in U.S. Pat. No. 5,016,662 issued May 21, 1999 to Crotts and Rambo. Another example is illustrated in U.S. Pat. No. 5,161,557 issued Nov. 10, 1992 to L. Scheiter.
The Seakan, Schleeter, Crotts et al and Scheiter systems are all of the “gantry” type; i.e., they all involve the use of an arch-shaped structure which rolls forward and backward along spaced, parallel floor tracks while passing over the vehicle. Crotts et al recognizes the desirability of laterally adjusting the position of the spray bars on one side of the arch according to variations in vehicle width.
Non-gantry pressure washers are also known in the art. One such washer comprises an overhead support for an inverted L-shaped spray arm which carries both vertically and horizontally-aimed spray nozzles and which can move longitudinally, laterally, and pivotally to circumscribe a parked vehicle. The pivot point for the spray arm is essentially at the intersection of the vertical and horizontal legs of the arm. This creates certain inefficiencies; for example, when traversing the side of a vehicle, the arm goes beyond the rear end of the vehicle stops and pivots 90° to begin a sweep of the rear surface. In so doing, the downwardly-directed nozzles cover a sector-shaped area of the trunk lid three times and the horizontally-directed nozzles spray into empty space for a significant period of time. At a minimum, this is wasteful of chemicals.